The present invention relates to a liquid developer device for a recording material, comprising at least one developer electrode which is connected with a conveying device for liquid developer for rendering visible the respective latent electrostatic image on the recording material.
A liquid developer device of this type is known from German Auslegeschrift No. 22 33 628. In this device, an arc-shaped developer electrode is arranged at a predetermined distance from the recording material which is in the form of a drum, so that a gap is formed. By a conveying device, the liquid developer is transported to the gap, in order to render visible the latent electrostatic image present on the drum-shaped recording material. The distance between the developer electrode and the drum-shaped recording material is adjusted by means of a distance regulating device which is equipped with slide members or rotatable rollers. The slide members or rotatable rollers, which are mounted at the ends of the developer electrode, maintain a defined distance between the recording material and the developer electrode. Additionally, springs are provided which force the distance regulating device into contact with the drum-shaped recording material. However, a relatively high constructional expense is required to ensure a uniform distance between the recording material and the developer electrode.
German Auslegeschrift No. 23 37 180 discloses a developer electrode for the cascade development of latent electrostatic images with a developer mixture. This electrode comprises a plurality of electrically conductive segments which are arranged along the width of the image area at equally spaced intervals, close to the image area to be developed. The segments are composed of angular metal sheets, the lateral edges of which are inserted into parallel slots provided in guide plates. Each of the sheet segments comprises a damming-up section and an electrode section which forms an obtuse angle with the damming-up section, the damming-up sections of two neighboring segments in each case forming a reservoir for the developer mixture delivered from above.
The developer electrode for powdery developer mixtures in accordance with German Offenlegungsschrift No. 2,164,494 (=U.S. Pat. No. 3,897,750) is pivotally mounted on a shaft and a spacing element is arranged at each side of the developer electrode.
A common feature to all these known developer electrodes, whether they are used for liquid or powdery developers, is that the mechanical expense necessary to maintain the gap between the developer electrode and the recording material carrying the latent electrostatic charge image to be developed is considerable.